certain Cali-emissions Hondas
Every time I roam the boneyard I have to stop at Hondas to look for 5-wire O2 sensors, never once spotting one. I remember reading they were only on some "clean burn" motor or something like that (wasn't paying full attention I guess) but now you've clinched it for me with the notion of California emissions build. Not likely I'll find anything that exotic or recent in our eastern pick'n'pulls.

Mostly I wanted a wideband sensor (and the controller from Oz) to build a poor substitute for a gas analyzer, rather than a fixed a/f meter.
--
Art Benstein near Baltimore